Chlorination of carbohydrates and derivatives thereof, such as sugars and their esters, has been generally known. For example, chlorination of sucrose to produce sucralose, or 4,1′,6′-trichloro-4,1′,6′-trideoxygalactosucrose, which is an artificial sweetener with a sweetness intensity many times that of sucrose, has been disclosed in U.S. Pat. No. 4,980,463; WO 2008/052076 A2, U.S. 2007/0100139 A1, and U.S. 2007/0207246 A1. Sucralose can be made by chlorination of a sucrose ester such as sucrose-6-acetate or sucrose-6-benzoate. However, the yields reported in the art for sucralose-6-ester are generally low. For example, the '463 patent discloses examples of preparing sucralose-6-benzoate in molar yields ranging from 31.9% to 60%. WO '076 discloses examples of preparing sucralose-6-acetate in a molar yield of 62.5%.
The foregoing shows that there exists an unmet need for preparing polychlorinated carbohydrates or derivatives thereof, particularly sucralose-6-ester in high molar yields.